This section provides background information related to the present disclosure which is not necessarily prior art.
In various manufacturing processes, such as manufacturing in the automobile industry, sheet metal panels or blanks may be stamped, where the sheet metal panel is pressed between a pair of dies, to create a complex three-dimensional shaped component. A sheet metal blank is usually first cut from a coil of metal material. The sheet metal material is chosen for its desirable characteristics, such as strength, ductility, and other properties related to the metal alloy.
Different techniques have been used to reduce the weight of a vehicle, while still maintaining its structural integrity. For example, tailor-welded blank assemblies are commonly used to form structural components for vehicles that need to fulfill specialized load requirements. For example, the B-pillar structural component of a car body desirably exhibits a relatively high structural rigidity in the areas corresponding to the body of the occupant, while having increased deformability in the lower region at or below the occupant's seat to facilitate buckling of the B-pillar below seat level when force or impact is applied. As the structural component has different performance requirements in different regions, such a component has been made with multiple distinct pieces assembled together to form what is known as a “tailored blank assembly” or “tailored weld assembly” (also often referred to as a “tailor welded blank,” or “tailor welded coil”). By way of non-limiting example, tailor welded blank assemblies may be used to form structural components in vehicles, for example, structural pillars (such as A-pillars, B-pillars, C-pillars, and/or D-pillars), hinge pillars, vehicle doors, roofs, hoods, trunk lids, engine rails, and other components with high strength requirements.
A tailored blank assembly typically includes at least one first metal sheet or blank and a second metal sheet or blank having at least one different characteristic from the first sheet. For example, steel blanks or steel strips having different strength, ductility, hardness, thicknesses, and/or geometry may be joined. After joining, the desired contour or three-dimensional structure is created, for example, by a cold forming process or hot forming process (e.g., like the stamping process described above). Thus, adjoining edges of the first and second sheets may be metallurgically or mechanically interlocked together, for example, by making a weld, junction, or other connection along the adjoining edges to interlock them with one another. Thereafter, the permanently affixed sheets or blanks may be processed to make a shaped or formed sheet metal assembly product. Notably, the tailor blank assembly is not limited to solely two sheets or blanks, rather three or more sheets or blanks may be joined together and shaped to form the assembly.
However, creating tailor blank assemblies is relatively cost-intensive due to the numerous steps and manufacturing processes involved. For example, the initial work piece blanks need to be individually cut, then joined in an assembly process, followed by the forming or shaping processes. In addition, issues with the structural component may potentially arise due to the presence of a joint or junction, such as a weld line. For example, the weld line or connection between the blanks may provide a site for localized strain that may alter the properties of the structural component and/or potentially cause premature failure. Further, in subsequent hot forming processes, the effect of the heat from welding may cause changes in the welding seam that can ultimately lead to softening at the welding seam(s) in the finished component, which could potentially compromise the quality and functionality of such a tailor blank assembly. It would be desirable to develop alternative new methods for forming structural components that must exhibit variable properties in different regions, especially high-strength components that can replace conventional tailor blank assemblies.